Any other dads here juggling work, study and parenting?

I've been in this very same boat before and I still am in some ways. Totally understand your post.
I found that coming home and studying in the evenings alongside the kids works well. By this I mean when you sit down to study, the kids sit down and do their own homework also. I tend to sit mine in my office on the desk not far away. One of them has less ability to focus than the other so benefits more from being under closer 'supervision'. Once their homework is finished, they can sit quietly and read their reading books until you are done or you're happy for them to do their own thing.
If nothing else this begins to teach them that a lot of people have to do 'homework' of some sort and that there is a time and a place to do it, after school, at home and in an environment with minimal other distractions. My office is purposely designed to be a place of work and there deliberately aren't any distractions or posters or anything very shouty or attention grabbing in the room. Even my bookshelves are loaded with ominous looking textbooks in the main so they aren't exactly distracting, either.
In the main I've long since organised my time using Outlook and the calendar function. University doesn't really give you much choice in that as most of them provide you with your calendar via this medium. Once you've become used to using it, it's almost the default choice from then on. I also keep a written paper diary but this is more a working and clinical type note-taking document and a place to write things, important dates, events or reminders. I also record work shifts and other things in it. If I was disciplined enough I could write all this in outlook but for some reason I like writing pens on paper and it's a carry over from my work in my previous lives. A small notebook holds other details and fits in my pocket whereas my diary is near A4 sized (a week to view). In the past I had a great desk blotter to scribble on but don't have one at the minute.
I try to balance time spent studying or doing their homework with recreational or fun activities at other times. I figured a sort of 5 sessions of homework is roughly equal to 2 small parent-led activities or 1 larger more significant one. Of course, this is easier with a single child situation as you don't have to seek agreement between them on what the activity might be.
In the past I think I've had times where I've felt guilty because it's occurred to me that I'm selfishly investing all this time and effort into my career and that is directly at the expense of child-parent time. I remember then that they only go through childhood once and parents never get that time back. But this has to be tempered with the reality that you're teaching them that hard work and long term commitment to something is a good thing and more to the point, for most people in any vocation, you aren't magically at home at 3pm every day after finishing work and able to spend the next 6 hours until bedtime doing whatever you please. In my former lives I had similarly demanding jobs and was often the last person home or the last person to leave the office or else I'd be sat working at home from 7-9pm after having driven home, eaten something and then get in front of a computer. Even the serious hedge fund managers in London earning 200K a year won't be leaving the office at 2pm and larking about the rest of the day living some Instagram life. Virtually all the professionals and high-income people I know are all equally putting effort in at the coal face way outside what would be considered usual office hours which is part of what makes them so successful in the first place. Children need to realise this early on: if you want success and nice things and the desired degree of financial freedom in life, it simply doesn't happen by default.
One thing I realised quite early on after is that kids in reality just want you to spend time with them. Toys, gifts, objects and expensive outings aren't actually much outside of being a distraction and an excuse to get out of the house. I've done my utmost not to be one of those parents who completely absolves their duties to a touchscreen. So far so good, I think.

big big thanks for this!!!!!

Interested to hear why you think it's different for dads?

Interested to hear why you think it's different for dads?

It would be harder for mothers who are in full time, I can near guarantee it. Children require a lot more input from mum I think. It's a different requirement. I don't know how mums studying full time do it. A lot more dedication and focus than I ever had probably.